The present invention relates to compositions for the fixation of cells and tissues and to methods for the fixation of cells and tissues using as the fixing agents certain compounds.
The objective of tissue fixation is to provide as much detail of the cell as possible. To do this, it is necessary to maintain the cells in their original unaltered morphology so that maximum cellular detail is observed under the microscope. With the development of immunostaining there is also the requirement that the antigens of the cells are not altered by the method of fixation or stabilization. Although the microscope is the usual means for examining cells that are fixed and stained, they may also be examined by the laser or the flow cytometer. The flow cytometer is an important method for examining a large number of cells in a brief time.
The usual formulations for stabilization of cells contain one or more agents which react vigorously with the proteins of the cells to denature, coagulate and insolubilize the components of the cell. Typical of this type of agent is picric acid, mercuric ions, formaldehyde and glutaraldehyde. In addition, some less toxic compounds which can also denature and stabilize the proteins are acetic and formic acid. Unfortunately, the toxicity associated with these compounds renders their use less than satisfactory.